1. Field of the Invention
The present invention is related to illumination intensity uniformity, ellipticity and telecentricity control using radiation absorbing fluids.
2. Background Art
In a pattern generating environment that patterns an impinging beam of radiation, which is later projected onto an object, controlling characteristics of the beam and/or the patterned beam is critical. This is because the beam and/or the patterned beam have to be precisely controlled in order to form accurate patterns on the object.
Generally, patterning generating systems use static optical systems, which are typically designed and manufactured for each application of the patterning system in order to produce the light beams with desired characteristics. In the static optical system example, when a change in illumination characteristics is desired or needed, a new optical system must be designed and manufactured. Also, changing of an output of an illumination source with time cannot normally be accounted for in a static optical system, which can result in less than desirable patterns being formed on the object.
In other illumination control methods, corrections are made by throwing away light in areas with unwanted light characteristics and/or corrections are being performed by relatively slow mechanical devices, which can substantially reduce throughput.
Further, in some examples, by correcting for one optical characteristic, e.g., light intensity uniformity, other characteristics become undesirable, e.g., ellipticity and/or telecentricity.
Therefore, what is needed is a system and method utilizing a dynamic optical system that is adjustable in response to measured or detected characteristics of an illumination beam and/or patterned illumination beam.